From: Theo Bekkers on
Hammo wrote:
> , "Iain Chalmers" wrote:

>> If your headlights
>> draw an extra 120W then the motor needs to put out an extra 120W - if
>> you factor in inefficiencyin the alternator (which is unlikey to be
>> any better that 80%) its going to be more like 150W. Add in the
>> running lights and you might get as high as an extra 200W needed
>> from the engine.

> I'd like to see your calculations! Please consider diameter of the
> pulleys of both crank and alternator, torque required and current and
> volatge flow, also for switched and non-switched systems.

Why all this irrelevant obfuscation? Oh, Hello Hammo.

>> That's not going to make much of a dent on Nev's 5.7L V8, but it's
>> over 10% of the total max output of a Deux Chevaux.

> 10 per cent?

Yes Hammo, 10% does mean 10 per cent.

>> Yup, you're right there. It's true that lights require power, but
>> it's not _much_ power...[1]

> If it is so small you cannot measure it, how can be called a waste?

If it is produced and not used, it's probably wasted.

I must say I'm a little surprised that modern bikes use total waste
regulators. I haven't looked into it and most schematics would show a little
box marked regulator with no indication of what it contains or how it works.
I thought that kind of 'engineering' went out with the Triumph Zener diode.
Surely you only need to encapsulate a couple of components to make a switch
mode regulator. Otherwise you've got a 400-500 watt heater. In that size the
regulator would need to be glowing. People heat their bedrooms with that
much power.


From: jlittler on
On Feb 9, 12:19 am, "Knobdoodle" <knobdoo...(a)> wrote:
> "G-S" <g...(a)> wrote in message
> news:12slpc3am5v613f(a)
> > Nev.. wrote:
> >> GB wrote:
> >>> "Nev.." <i...(a)> wrote in
> >>>news:45ca4f55$0$25321$5a62ac22(a)
> >>>> And you very neatly ignored the bit where I also found that it did not
> >>>> affect the fuel flow and therefore did not use any more fuel... no
> >>>> wait.. you poo-poo'd that because it didn't suit your argument. BZZT.
> >>> I didn't ignore it at all. In fact I addressed it quite
> >>> comprehensively. Your fuel flow meter is not up to the task of measuring
> >>> fuel flow with sufficient accuracy or repeatability
> >>> to demonstrate the so-fundamental-that-it-shouldn't-need-discussing,-
> >>> much-less-demonstrating principle of physics that's being discussed.
> >> So for all intents and purposes, the amount of additional fuel consumed
> >> when the headlights are turned on is immeasurable, so this "lights on =
> >> more fuel" business exists in theory only.
> > _Not_ immeasurable... just not measurable by a standard car consumption
> > gauge.
> > We have flow rate meters at work that are sensitive enough to measure this
> > effect.
> > Place the reading device at the test point, turn on the coach headlights,
> > driving lights and interior lights and the fuel consumption at idle
> > increases measurably as the engine takes the additional load of driving
> > the dual alterators to produce more current (averaging an extra 60 amps
> > according to the current draw gauge).
> > No I can't do this test moving as the test equipment isn't that movable,
> > but that doesn't invalidate the results.
> I'd reckon that the trip computer doesn't even HAVE a flow-meter! (Or at
> least doesn't have one that measures flow that accurately)
> I reckon it just measures the RPM and throttle position (and maybe 10 other
> inputs) and gives you the pre-calculated result.

AFAIK; pretty much right. As I understand it, RPM and the input of
either the air flow meter(older cars) or throttle position
sensor(modern cars) and a few other things like temp and o2(lambda)
sensor give you the injection duration which is then used to calculate
fuel consumed and divided by distance travelled to give litres per


From: Theo Bekkers on
Hammo wrote:

> Goes to insert joke (and thinks better of it).

>'s all about me!!

We knew that already.


From: Theo Bekkers on
Nev.. wrote:
> G-S wrote:

>> We have flow rate meters at work that are sensitive enough to measure
>> this effect.

> So does my car. It doesn't measure any change.

Well, I hope your car flow rate meter is better than the one in my Norge. I
go 400 kms with a 23 litre tank, the consumption gauge says 5.6 l/100km, 20
litres fill it to the brim.

NB:- because a measuring device indicates 4 significant digits does not mean
that it has more than a 2 digit accuracy.


From: jlittler on
On Feb 9, 12:58 am, atec <"atec77 "> wrote:
> Andrew McKenna wrote:
> > sharkey wrote:
> >> Andrew McKenna <NOcmorSPAM3...(a)> wrote:
> >>> I think your critics are thinking of their bicycles with dynamo
> >>> powered headlights :-) More electrical load might make you discover
> >>> that you need to push harder to achieve the same results but there's
> >>> no way the dynamo itself gets harder to spin.
> >> What? You need to push harder to spin it but it doesn't get harder to
> >> spin?
> >> -----sharks
> > No, you need to push harder to get the result if you add electrical
> > load. It cannot possibly get harder to spin.
> Now thats wrong in so many ways .

Actually he's dead right if you read it carefully - typical engineer's
wording though. They never speak english.

The MECHANICAL load is unchanged IE the effort to physically spin the
metallicy bits around will be unchanged regardless of electrical load.

HOWEVER if you then add the bit you guys are busy arguing about -
which strictly speaking isn't mechanical load as such within the
alternator/dynamo/generator (although it will be EXTERNAL to the
system) you are adding additional torque requirements to overcome the
additional physical resistance to turning created by the electrical

(not a 100% sure I've turned that into English successfully, it's
tough being a translator ;-)

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